From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-11.4 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 97A82C41604 for ; Wed, 7 Oct 2020 16:30:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 342552064E for ; Wed, 7 Oct 2020 16:30:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Y4+NKXdl" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727937AbgJGQah (ORCPT ); Wed, 7 Oct 2020 12:30:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50502 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727908AbgJGQah (ORCPT ); Wed, 7 Oct 2020 12:30:37 -0400 Received: from mail-il1-x144.google.com (mail-il1-x144.google.com [IPv6:2607:f8b0:4864:20::144]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D775CC061755 for ; Wed, 7 Oct 2020 09:30:36 -0700 (PDT) Received: by mail-il1-x144.google.com with SMTP id o9so2878313ilo.0 for ; Wed, 07 Oct 2020 09:30:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=UYMk+BlOXeIbztTTmOGtrLRWb7ewhHw6QepmeLnJlMQ=; b=Y4+NKXdlYiaTxkXT9l/2+Nk56HfwQ2izplaW+tMW3d0vI4hwfIC5V8T2ruDvM0wUNb yAPjVLoCd3dSKe2CMd6GozDwwbjRFayGNqlAb00cDAldU9bBDMLQfDJNr1gfV5cHAAaf /Z77J4+EhN66Oxu7/U6S2CevfxJwD8Y/meciKSGT0YiMbOeBYXIyiKiYjReB102VMaQ2 pk01mw9bZbvbUxpipQXJIWIZ8X+p311eE3aTLuxeb5hV41N5AtMTbTX46pfwersSs8SQ IxEnrPM5BvSJ9lgamii7Kt//gXnrI3fPFKGpbt95RQHe2+2TJ2LX0CESU0s2JRmQ1an/ IxRQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=UYMk+BlOXeIbztTTmOGtrLRWb7ewhHw6QepmeLnJlMQ=; b=nIz+YmZMtfhj7OuX56+lcfBWIk1ZCOZBiZVZnMCMtyb/NA8z5K4b7/qNve2TuhN1up CYjGiyMzM63RAUHM/R3EzQ2Cn6csMbuCeOrMTQ/bh6up9DiZxPEeglF4SbMjb5aTTe1r wUa74K4tL44U3uKw2dRC1doSwxCRy5ZY4ZBK4k7kFN6c0xYw8tAMde+iPbkhbyWuFBAC Svltfu63dJCqQC2m3VXPuuMZ8UerKfnf5MgAwhcDTfJV+/R3BGuahe0qiIQkHfoWivtg XSdd/5YMHaeW+sGuTmmaoG+bxCTMwHdynLi9W0A3AZ1834wSgC6EEsk780ppDZNV04VG Sb/w== X-Gm-Message-State: AOAM532FS5BW+YRexU+e3K6sYPrREMK6eiBTF/MC3ft0OpNSYkPxZ5dq 22ONmyEp+U1sU+Yva1gVNA6hvI04rCFESZzsgWpv4g== X-Google-Smtp-Source: ABdhPJz1pivHDuMpRIp1ymbBND8FIwBI+9YWjqbDyuFQsSBKh6gKtzo/VQ/hpFczpGrC3Z/Fe1wNF06wJy3f0eJ9Kos= X-Received: by 2002:a92:cbcd:: with SMTP id s13mr3157728ilq.306.1602088235893; Wed, 07 Oct 2020 09:30:35 -0700 (PDT) MIME-Version: 1.0 References: <20200925212302.3979661-1-bgardon@google.com> <20200925212302.3979661-19-bgardon@google.com> <44822999-f5dc-6116-db12-a41f5bd80dd8@redhat.com> In-Reply-To: <44822999-f5dc-6116-db12-a41f5bd80dd8@redhat.com> From: Ben Gardon Date: Wed, 7 Oct 2020 09:30:24 -0700 Message-ID: Subject: Re: [PATCH 18/22] kvm: mmu: Support disabling dirty logging for the tdp MMU To: Paolo Bonzini Cc: LKML , kvm , Cannon Matthews , Peter Xu , Sean Christopherson , Peter Shier , Peter Feiner , Junaid Shahid , Jim Mattson , Yulei Zhang , Wanpeng Li , Vitaly Kuznetsov , Xiao Guangrong Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Fri, Sep 25, 2020 at 6:09 PM Paolo Bonzini wrote: > > On 25/09/20 23:22, Ben Gardon wrote: > > + for_each_tdp_pte_root(iter, root, start, end) { > > + if (!is_shadow_present_pte(iter.old_spte) || > > + is_last_spte(iter.old_spte, iter.level)) > > + continue; > > + > > I'm starting to wonder if another iterator like > for_each_tdp_leaf_pte_root would be clearer, since this idiom repeats > itself quite often. The tdp_iter_next_leaf function would be easily > implemented as > > while (likely(iter->valid) && > (!is_shadow_present_pte(iter.old_spte) || > is_last_spte(iter.old_spte, iter.level)) > tdp_iter_next(iter); Do you see a substantial efficiency difference between adding a tdp_iter_next_leaf and building on for_each_tdp_pte_using_root with something like: #define for_each_tdp_leaf_pte_using_root(_iter, _root, _start, _end) \ for_each_tdp_pte_using_root(_iter, _root, _start, _end) \ if (!is_shadow_present_pte(_iter.old_spte) || \ !is_last_spte(_iter.old_spte, _iter.level)) \ continue; \ else I agree that putting those checks in a wrapper makes the code more concise. > > Paolo >